Immune & Inflammatory Peptides

Immune and anti-inflammatory peptides modulate the body's defence and repair systems at the molecular level. Unlike immunosuppressants, which globally dampen immune function, these compounds typically act as immune regulators — enhancing adaptive immunity where it is deficient, suppressing excessive inflammatory signalling where it causes damage, and restoring immune homeostasis in dysfunctional states.

Thymosin Alpha-1 (TA1, Zadaxin) is the most clinically validated peptide in this category. A 28 amino acid peptide naturally produced by the thymus gland, TA1 enhances T-cell maturation and activation, upregulates NK cell cytotoxicity, and promotes dendritic cell function. It is approved as a medicine in over 35 countries for hepatitis B and C treatment, certain cancers, and immunocompromised states. In ageing, thymic involution reduces TA1 production — making supplementation potentially relevant for immunosenescence.

LL-37 is the only known member of the human cathelicidin family of host-defence peptides. It is produced by neutrophils, macrophages, mast cells, and epithelial cells at sites of infection or inflammation. LL-37 has direct antimicrobial activity against a broad spectrum of bacteria, fungi, and viruses, and also modulates the innate immune response — promoting wound healing, angiogenesis, and clearance of cellular debris. Its dual antimicrobial and immunomodulatory role makes it relevant for research into chronic infections, wound healing, and mucosal immunity.

KPV (Lys-Pro-Val) is a C-terminal tripeptide of alpha-MSH with potent anti-inflammatory properties. It directly inhibits NF-kB activation in intestinal epithelial cells and macrophages, suppressing pro-inflammatory cytokine production (TNF-alpha, IL-6, IL-1beta). Preclinical data shows efficacy in models of IBD (inflammatory bowel disease), colitis, and skin inflammation. KPV's small size allows for oral and topical administration routes being explored in research.

In the UK, Thymosin Alpha-1 is not MHRA-licensed but can be obtained as an unlicensed medicine on a named-patient basis with prescriber authorisation. LL-37 and KPV are unregulated research chemicals. This category has significant relevance to emerging research in long COVID immune dysregulation, autoimmune conditions, and age-related immune decline.